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EN60950-1:20067 a" l( k+ j$ E* N9 Z: _; k3 x
4.2.7 Stress relief test
, U, Q+ D. |# R2 `2 TENCLOSURES of moulded or formed thermoplastic materials shall be so constructed that any
, [$ q* Z s0 D7 `shrinkage or distortion of the material due to release of internal stresses caused by the
% Q. h1 b0 t5 k0 j Q8 Hmoulding or forming operation does not result in the exposure of hazardous parts or in the
- M [' V' a4 o% Y2 I& W0 B1 n, treduction of CLEARANCES or CREEPAGE DISTANCES below the values specified in 2.10 (or8 u# E$ Y# W1 M6 v, _
Annex G).5 ^: ~5 x/ ~" J" p4 S; [* z& L
Compliance is checked by the test procedure described below or by the inspection of the2 n0 V: w$ B& X/ a F
construction and the available data where appropriate.
) o i" n9 [5 P3 V! {) M; @" P UOne sample consisting of the complete equipment, or of the complete ENCLOSURE together
& `8 d" g7 Q& v( kwith any supporting framework, is placed in a circulating air oven (according to
5 j; Z+ I! C" U# Y' qIEC 60216-4-1) at a temperature 10 K higher than the maximum temperature observed on the
2 G- I. B6 {1 `3 w8 L# b. j# NENCLOSURE during the test of 4.5.2, but not less than 70 ° C, for a period of 7 h, then permitted
1 J$ S. h; ^3 ]) e' E; f6 D: jto cool to room temperature.
) q# J, a+ ^0 j) O4 `2 @With the concurrence of the manufacturer, it is permitted to increase the above time duration.
- s$ V2 V3 ~* D o: z4 N* C/ NFor large equipment where it is impractical to condition a complete ENCLOSURE, it is permitted
8 Z/ `; F$ ~ }9 H* Bto use a portion of the ENCLOSURE representative of the complete assembly with regard to) q+ I$ w$ g# @$ k& K- r
thickness and shape, including any mechanical support members.
1 f; n! ~, c7 K) h0 l6 [3 {NOTE Relative humidity need not be maintained at a specific value during this test.
- {% H6 L, A+ d5 O2 s+ U0 F6 ZIf the above test is conducted, the compliance criteria of 4.2.1 apply. |
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